Production of artificial materials



Patented Aug. 24, 1937 UNITED STATES PATENT OFFICE 10 Claims.

This invention relates to the production or treatment of artificial filaments, threads, yarns, ribbons and the .like, and particularly to processes whereby the materials are subjected to a stretching operation.

U. S. Patent No. 1,709,470 describes processes in which cellulose acetate artificial silk filaments are stretched beyond their elastic limit at any suitable stage of their manufacture after the artificial silk is in a fully set and finished condition, whereby they are rendered wholly or partially resistant to deterioration when they are subsequently treated with hot aqueous liquids and whereby their tensile strength may be increased. The specification further describes the use of assisting agents, for example, acetone, ethyl alcohol, formaldehyde and glycerine, to assist in the stretching.

Again, in U. S. application S. No. 378,684 filed 16th July, 1929 I have described processes in which artificial filaments, threads and the like are stretched during their travel from one point to another, and in this case also stretching is facilitated by the action of solvents or swelling agents for the cellulose derivative concerned, for example the monoand di-ethers of olefine glycols and polyolefine glycols and mono-, di- "and tri-acetins.

In my British Patent No. 336,217, processes are described for improving the tensile strength of materials containing organic derivatives of cellulose by subjecting them, either in the finished condition or continuously with their production by dry or semi-dry spinning processes, to the action of neutral organic solvents in relatively high concentration, while in U. S. application S. No. 402,785 filed 26th October, 1929, are described processes for the stretching of wet spun products continuously with their production, in which solvents for the cellulose derivatives are incorporated in the dope itself, in the coagulating or after-treatment bath, or in more than one of these baths. v

I have now discovered that diand other polyglycerols and their inorganic and organic esters and ethers, including cyclic ethers and etheresters, are very suitable substances for use in the stretching of artificial materials containing organic derivatives of cellulose, for example by any of the processes described in the above mentioned specifications. As examples of such substances may be mentioned diglycerine, the substance known as poly-glyceryl acetate, the morio-, triand tetra-acetates of diglycerine, the diethyl de-- rivative of diglycerine chlorhydrin, the mono- In Great Britain July 21, 1932 acetyl derivative of diglycerine trichlorhydrin and the acetyl derivatives of triglycerine tetrachlorhydrin. Further, condensation products of polyglycerol and their esters and ethers may also be employed, for example, di-glycide, diacetyl-diglycide and di-benzoyl-diglycide. The process of the present invention may be carried out either continuously with the production of the artificial materials, whether by wet or dry spinning processes, as a separate operation while the materials are travelling from one point to another, or upon hanks, bobbins or other packages. Stretching may be effected in a single stage, or in more than one stage. It may also be applied to the treatment of yarns and the'like in warp formation, as is described for example in- U. S. application S. No. 573,424 filed 6th November, 1931. When the process is carried out continuously with the production of the artificial materials the poly-glycerine or other similar compound may be incorporated in the dope itself or in the coagulating bath or in an after-treatment bath.

The artificial materials may, if desired, be treated with the substances employed according to the present invention at normal temperatures, though, particularly in the case whenpolyglycerines or ethers of poly-glycerines are employed, the treatment may be carried out at elevated temperatures, for example at to 100, or even 200 C. In general the substance will be applied as a solution or dispersion in an aqueous or organic medium, though the use of the substance in the absence of such media is not excluded. The diand poly-glycerines and their ethers are hydroscopic bodies and take up water from the atmosphere, and in the case of these compounds it may not be necessary to add any diluent beyond the water which they normally contain. When moderate temperatures are employed, very suitable diluents are water and relatively low boiling organic liquids having no action upon the cellulose derivative, for example alcohol, ethers, and benzene, toluene and other hydrocarbons, but when relatively elevated temperatures are employed, it is desirable to use higher boiling compounds, for example amyl alcohol, tetrahydroand decahydro-naphthalene, I

ployed with they higher ethers of the polyglycerines and with their esters or ether-esters.

Other substances which are solvents, latent solvents or swelling agents hereinafter referred to 5 as solvents for the cellulose derivative may be employed in conjunction with the compounds which form the special feature of the present invention, either in the presence or in the absence of diluents. Suitable solvents are those which are of greater volatility than the compounds which form the particular feature of the present invention. Examples of these are acetone, diacetone alcohol, monoor di-ethers or esters of olefine glycols or mixed ether-esters thereof,

e. g. glycol mono-acetate and methyl glycol "mono-acetate, dioxane, methylene ethylene oxide, methylene chloride and dichlorethylene. Solvents should not of course be used in such concentration that any pronounced solvent action on the cellulose derivative occurs. Such solvents,

' latent solvents or swelling agents may be applied simultaneously with'the poly-glycerine or derivative used according to the present invention, or as a separate operation. Thus, filaments of cellulose acetate may be passed through a bath containing aqueous dioxane and then treated with a solution of a poly-glycerine, or a vyarn treated with a poly-glycerine derivative may be stretched and may be simultaneously treated with one of the above agents e. g. by carrying out the stretching process in a solvent laden atmosphere.

The ,concentration of the di-glycerine or other compound employed according to the present invention will of course depend upon the other 5 conditions prevailing during the treatment and the results it is desired to obtain, for example i the temperature at which it is applied, the type of artificial material and the stretch which it is desired to produce, but in general concentra tions of from 30 to 50% up to 70% have been found of value, and, as has been mentioned above, the poly-glycerines and the like may even be employed in the absence of a diluent.

v The poly-glycerines or their esters or ethers may be applied to the artificial materials by passing the materials through baths or by immersing them therein, or by means of wicks or rollers or by spraying or otherwise projecting the substance on to the materials.

The application of the poly-glycerines and their derivatives to the materials may take place prior to or simultaneously with stretching, and, as stated above, stretching may be carried out in a single stage or in two or more stages, as is described, for example, in U. S. application S. No. 573,424 filed 6th November, 1931. Two or more softening treatments of diflerent strength may be employed, as is described for example in my I U. S. application S. No. 638,776 filed 20th Octo- 0 her, 1932. Again, when the application of the diglycerine or ,other substance takes place simultaneously with stretching, means may be employed whereby the action of the stretching force is limited to the portion of filaments or other 5 materials which have already reached a substantially softened condition, as is described in U. S. application S. No.'672 ,800 filed May 25, 1933.

The materials treated according to the present invention may be subjected to a shrinking proc- 70 ess in order to improve their extension either before or after stretching, as is described, for example, in U. S. application, S. No. 611,240, filed 13th May, 1932, and U. Sjapplication, S.

No. 672,805, filed May 25, 1933.-'Further, salts;

75 sugars or other inorganic or organic compounds may be employed either in the baths in which the polyglycerine or derivatives are applied to the materials, or in subsequent treatment baths, in order to decrease the solubility of the substance in the nonsolvent medium, as is described for example in U. S. applications, S. Nos. 469,622, filed 21st July, 1930, 636,943, filed 8th October, 1932, and 638,179 filed 17th October, 1932. Again, the stretched filaments and the like may be subjected to a process of partial or complete saponification, either continuously with the stretching process or as a separate operation, e. g. by treatment with aqueous or alcoholic solutions of caustic alkali, as is described for example in my U. S. application, S. No. 655,778, filed 8th February, 1933.

The process of the present invention is of particular value in connection with the treatment of artificial filaments, threads, yarns, ribbons and the like made of or containing cellulose acetate,

but it is also applicable to materials containing other organic derivatives of cellulose, for example, cellulose formate, propionate, butyrate, nitroacetate and other esters or mixed esters of cellulose, ethers or mixed ethers of cellulose, for example ethyl, butyl and benzyl cellulose and mixed ether-esters, for example ethyl cellulose acetate and oxy-ethyl-cellulose acetate.

The following examples are given in order to illustrate the invention but it is to be clearly understood that the invention is not limited in any way thereto:-

Example 1 Example 2 A number of cellulose acetate threads from a creel of bobbins are carried through an aligning device and then in parallel formation under a roller rotating in a softening bath consisting of an aqueous solution containing 40-50% diglycide and 15-25% dioxane. The threads are kept apart .by one-or more reeds and pass along the bath to a draw roller rotating at such speed that the materials are stretched, e. g. to 200-300% of their original length. The materials are then washed, dried and wound.

What I claim and desire to secure by Letters Patent is:-

1. In the manufacture of artificial filaments, threads, yarns, ribbons and like materials comprising organic derivatives of cellulose, the step of bringing such materials to a softened condition by treatment with media containing substances selected from the group consisting of diand tri-glycerols, their condensation products, their esters, ethers and ether-esters and the esters-and ethers of such condensation products, and subjecting the softened materials to a stretching operation.

2. Process for the manufacture of artificial filaments, threads, yarns, ribbons and like materials, comprising extruding a solution containing an organic derivative of cellulose into a coagulating medium containing, in a concentration such that the materials are obtained in a softened condition, a substance selected from the group consisting of diand tri-glycerols, their condensation products, esters, ethers and ether-esters, and the esters and ethers of such condensation products, and subjecting the softened materials to a stretching operation; i

3. Process for the manufacture of artificial filaments, threads, yarns, ribbons and like materials, comprising extruding a solution containing cellulose acetate into a coagulating medium maintained at a temperature of at least C. and containing, in a concentration such that the materials are obtained in a softened condition, a substance selected from the group consisting of diand tri-glycerols, their condensation products, esters, ethers and ether-esters, and the esters and ethers of such condensation products. and subjecting the softened materials to a stretching operation.

4. Process for the manufacture of artificial filaments, threads, yarns, ribbons and like materials, comprising extruding a solution containing cellulose acetate into a coagulating medium containing, in a concentration such that the materials are obtained in a softened condition, a substance selected from the group consisting of diand triglycerols, their condensation products, esters, ethers and ether-esters, and the esters and ethers of such condensation products and a solvent for the cellulose acetate of greater volatility than said substance, and subjecting the softened 7 materials to a stretching operation.

5. Process for the manufacture of artificial filaments, threads, yarns, ribbons and like materials comprising extruding a solution containing cellulose acetate into a coagulating medium containing diglycerine in a concentration of 30-70%, and a solvent for the cellulose acetate of greater volatility than diglycerine, and subjecting the extruded materials to a stretching operation 6. Process for the manufacture of artificial filaments, threads, yarns, ribbons and like materials comprising extruding a solution containing cellulose acetate into a coagulating medium con-- taining .diglycerine mono-acetate in a concentration of 30-70%, and a solvent for the cellulose acetate of greater volatility than diglycerine mono-acetate, and subjecting the extruding materials to a stretching operation.

7. Process for the treatment of artificial filaments, threads, yarns, ribbons and like materials comprising an organic derivative of cellulose, comprising softening the formed materials with a medium containing a substance selected from the group consisting of diand tri-glycerols, their condensation products, esters, ethers and etheresters, and the esters and ethers of such condensation products, and subjecting the softened materials to a stretching operation.

8. Process for the treatment of artificial filaments, threads, yarns, ribbons and like materials comprising cellulose acetate, comprising softening the formed materials with a medium containing a substance selected from the group consisting of diand tri-glycerols, their condensation products, esters, ethers and ether-esters, and the esters and ethers of such condensation products and a solvent for the cellulose acetate of greater volatility than the said substance, and subjecting the softened materials to a stretching operation.

9. Process for the treatment of artificial filaments, threads, yarns, ribbons and like materials comprising cellulose acetate, comprising softening the formed materials with a medium containing diglycide in a concentration of from 30-70% and a solvent for the cellulose acetate of greater volatility than said substance, and subjecting the softened materials to a stretching operation whilst they are in Warp formation.

10. Process for the treatment of artificial filaments, threads, yarns, ribbons and like materials comprising cellulose acetate, comprising softening the formed materials with a medium containing diglycerine mono-acetatein a concentration of from 30-70% and a solvent for the cellulose acetate of greater volatility than said substance, and subjecting the softened materials to a stretching operation whilst they are in warp formation.

HENRY DREYFUS. 

